Contract Source Code:
File 1 of 1 : Oracle
// File: https://github.com/smartcontractkit/chainlink/evm-contracts/src/v0.4/interfaces/LinkTokenInterface.sol
pragma solidity ^0.4.24;
interface LinkTokenInterface {
function allowance(address owner, address spender) external view returns (uint256 remaining);
function approve(address spender, uint256 value) external returns (bool success);
function balanceOf(address owner) external view returns (uint256 balance);
function decimals() external view returns (uint8 decimalPlaces);
function decreaseApproval(address spender, uint256 addedValue) external returns (bool success);
function increaseApproval(address spender, uint256 subtractedValue) external;
function name() external view returns (string tokenName);
function symbol() external view returns (string tokenSymbol);
function totalSupply() external view returns (uint256 totalTokensIssued);
function transfer(address to, uint256 value) external returns (bool success);
function transferAndCall(address to, uint256 value, bytes data) external returns (bool success);
function transferFrom(address from, address to, uint256 value) external returns (bool success);
}
// File: https://github.com/smartcontractkit/chainlink/evm-contracts/src/v0.4/interfaces/OracleInterface.sol
pragma solidity ^0.4.24;
interface OracleInterface {
function fulfillOracleRequest(
bytes32 requestId,
uint256 payment,
address callbackAddress,
bytes4 callbackFunctionId,
uint256 expiration,
bytes32 data
) external returns (bool);
function getAuthorizationStatus(address node) external view returns (bool);
function setFulfillmentPermission(address node, bool allowed) external;
function withdraw(address recipient, uint256 amount) external;
function withdrawable() external view returns (uint256);
}
// File: https://github.com/smartcontractkit/chainlink/evm-contracts/src/v0.4/interfaces/ChainlinkRequestInterface.sol
pragma solidity ^0.4.24;
interface ChainlinkRequestInterface {
function oracleRequest(
address sender,
uint256 payment,
bytes32 id,
address callbackAddress,
bytes4 callbackFunctionId,
uint256 nonce,
uint256 version,
bytes data
) external;
function cancelOracleRequest(
bytes32 requestId,
uint256 payment,
bytes4 callbackFunctionId,
uint256 expiration
) external;
}
// File: https://github.com/smartcontractkit/chainlink/evm-contracts/src/v0.4/vendor/SafeMathChainlink.sol
pragma solidity ^0.4.11;
/**
* @title SafeMath
* @dev Math operations with safety checks that throw on error
*/
library SafeMathChainlink {
/**
* @dev Multiplies two numbers, throws on overflow.
*/
function mul(uint256 _a, uint256 _b) internal pure returns (uint256 c) {
// Gas optimization: this is cheaper than asserting 'a' not being zero, but the
// benefit is lost if 'b' is also tested.
// See: https://github.com/OpenZeppelin/openzeppelin-solidity/pull/522
if (_a == 0) {
return 0;
}
c = _a * _b;
assert(c / _a == _b);
return c;
}
/**
* @dev Integer division of two numbers, truncating the quotient.
*/
function div(uint256 _a, uint256 _b) internal pure returns (uint256) {
// assert(_b > 0); // Solidity automatically throws when dividing by 0
// uint256 c = _a / _b;
// assert(_a == _b * c + _a % _b); // There is no case in which this doesn't hold
return _a / _b;
}
/**
* @dev Subtracts two numbers, throws on overflow (i.e. if subtrahend is greater than minuend).
*/
function sub(uint256 _a, uint256 _b) internal pure returns (uint256) {
assert(_b <= _a);
return _a - _b;
}
/**
* @dev Adds two numbers, throws on overflow.
*/
function add(uint256 _a, uint256 _b) internal pure returns (uint256 c) {
c = _a + _b;
assert(c >= _a);
return c;
}
}
// File: https://github.com/smartcontractkit/chainlink/evm-contracts/src/v0.4/vendor/Ownable.sol
pragma solidity ^0.4.24;
/**
* @title Ownable
* @dev The Ownable contract has an owner address, and provides basic authorization control
* functions, this simplifies the implementation of "user permissions".
*/
contract Ownable {
address public owner;
event OwnershipRenounced(address indexed previousOwner);
event OwnershipTransferred(
address indexed previousOwner,
address indexed newOwner
);
/**
* @dev The Ownable constructor sets the original `owner` of the contract to the sender
* account.
*/
constructor() public {
owner = msg.sender;
}
/**
* @dev Throws if called by any account other than the owner.
*/
modifier onlyOwner() {
require(msg.sender == owner);
_;
}
/**
* @dev Allows the current owner to relinquish control of the contract.
* @notice Renouncing to ownership will leave the contract without an owner.
* It will not be possible to call the functions with the `onlyOwner`
* modifier anymore.
*/
function renounceOwnership() public onlyOwner {
emit OwnershipRenounced(owner);
owner = address(0);
}
/**
* @dev Allows the current owner to transfer control of the contract to a newOwner.
* @param _newOwner The address to transfer ownership to.
*/
function transferOwnership(address _newOwner) public onlyOwner {
_transferOwnership(_newOwner);
}
/**
* @dev Transfers control of the contract to a newOwner.
* @param _newOwner The address to transfer ownership to.
*/
function _transferOwnership(address _newOwner) internal {
require(_newOwner != address(0));
emit OwnershipTransferred(owner, _newOwner);
owner = _newOwner;
}
}
// File: https://github.com/smartcontractkit/chainlink/evm-contracts/src/v0.4/Oracle.sol
pragma solidity 0.4.24;
/**
* @title The Chainlink Oracle contract
* @notice Node operators can deploy this contract to fulfill requests sent to them
*/
contract Oracle is ChainlinkRequestInterface, OracleInterface, Ownable {
using SafeMathChainlink for uint256;
uint256 constant public EXPIRY_TIME = 5 minutes;
uint256 constant private MINIMUM_CONSUMER_GAS_LIMIT = 400000;
// We initialize fields to 1 instead of 0 so that the first invocation
// does not cost more gas.
uint256 constant private ONE_FOR_CONSISTENT_GAS_COST = 1;
uint256 constant private SELECTOR_LENGTH = 4;
uint256 constant private EXPECTED_REQUEST_WORDS = 2;
uint256 constant private MINIMUM_REQUEST_LENGTH = SELECTOR_LENGTH + (32 * EXPECTED_REQUEST_WORDS);
LinkTokenInterface internal LinkToken;
mapping(bytes32 => bytes32) private commitments;
mapping(address => bool) private authorizedNodes;
uint256 private withdrawableTokens = ONE_FOR_CONSISTENT_GAS_COST;
event OracleRequest(
bytes32 indexed specId,
address requester,
bytes32 requestId,
uint256 payment,
address callbackAddr,
bytes4 callbackFunctionId,
uint256 cancelExpiration,
uint256 dataVersion,
bytes data
);
event CancelOracleRequest(
bytes32 indexed requestId
);
/**
* @notice Deploy with the address of the LINK token
* @dev Sets the LinkToken address for the imported LinkTokenInterface
* @param _link The address of the LINK token
*/
constructor(address _link) public Ownable() {
LinkToken = LinkTokenInterface(_link); // external but already deployed and unalterable
}
/**
* @notice Called when LINK is sent to the contract via `transferAndCall`
* @dev The data payload's first 2 words will be overwritten by the `_sender` and `_amount`
* values to ensure correctness. Calls oracleRequest.
* @param _sender Address of the sender
* @param _amount Amount of LINK sent (specified in wei)
* @param _data Payload of the transaction
*/
function onTokenTransfer(
address _sender,
uint256 _amount,
bytes _data
)
public
onlyLINK
validRequestLength(_data)
permittedFunctionsForLINK(_data)
{
assembly { // solhint-disable-line no-inline-assembly
mstore(add(_data, 36), _sender) // ensure correct sender is passed
mstore(add(_data, 68), _amount) // ensure correct amount is passed
}
// solhint-disable-next-line avoid-low-level-calls
require(address(this).delegatecall(_data), "Unable to create request"); // calls oracleRequest
}
/**
* @notice Creates the Chainlink request
* @dev Stores the hash of the params as the on-chain commitment for the request.
* Emits OracleRequest event for the Chainlink node to detect.
* @param _sender The sender of the request
* @param _payment The amount of payment given (specified in wei)
* @param _specId The Job Specification ID
* @param _callbackAddress The callback address for the response
* @param _callbackFunctionId The callback function ID for the response
* @param _nonce The nonce sent by the requester
* @param _dataVersion The specified data version
* @param _data The CBOR payload of the request
*/
function oracleRequest(
address _sender,
uint256 _payment,
bytes32 _specId,
address _callbackAddress,
bytes4 _callbackFunctionId,
uint256 _nonce,
uint256 _dataVersion,
bytes _data
)
external
onlyLINK
checkCallbackAddress(_callbackAddress)
{
bytes32 requestId = keccak256(abi.encodePacked(_sender, _nonce));
require(commitments[requestId] == 0, "Must use a unique ID");
// solhint-disable-next-line not-rely-on-time
uint256 expiration = now.add(EXPIRY_TIME);
commitments[requestId] = keccak256(
abi.encodePacked(
_payment,
_callbackAddress,
_callbackFunctionId,
expiration
)
);
emit OracleRequest(
_specId,
_sender,
requestId,
_payment,
_callbackAddress,
_callbackFunctionId,
expiration,
_dataVersion,
_data);
}
/**
* @notice Called by the Chainlink node to fulfill requests
* @dev Given params must hash back to the commitment stored from `oracleRequest`.
* Will call the callback address' callback function without bubbling up error
* checking in a `require` so that the node can get paid.
* @param _requestId The fulfillment request ID that must match the requester's
* @param _payment The payment amount that will be released for the oracle (specified in wei)
* @param _callbackAddress The callback address to call for fulfillment
* @param _callbackFunctionId The callback function ID to use for fulfillment
* @param _expiration The expiration that the node should respond by before the requester can cancel
* @param _data The data to return to the consuming contract
* @return Status if the external call was successful
*/
function fulfillOracleRequest(
bytes32 _requestId,
uint256 _payment,
address _callbackAddress,
bytes4 _callbackFunctionId,
uint256 _expiration,
bytes32 _data
)
external
onlyAuthorizedNode
isValidRequest(_requestId)
returns (bool)
{
bytes32 paramsHash = keccak256(
abi.encodePacked(
_payment,
_callbackAddress,
_callbackFunctionId,
_expiration
)
);
require(commitments[_requestId] == paramsHash, "Params do not match request ID");
withdrawableTokens = withdrawableTokens.add(_payment);
delete commitments[_requestId];
require(gasleft() >= MINIMUM_CONSUMER_GAS_LIMIT, "Must provide consumer enough gas");
// All updates to the oracle's fulfillment should come before calling the
// callback(addr+functionId) as it is untrusted.
// See: https://solidity.readthedocs.io/en/develop/security-considerations.html#use-the-checks-effects-interactions-pattern
return _callbackAddress.call(_callbackFunctionId, _requestId, _data); // solhint-disable-line avoid-low-level-calls
}
/**
* @notice Use this to check if a node is authorized for fulfilling requests
* @param _node The address of the Chainlink node
* @return The authorization status of the node
*/
function getAuthorizationStatus(address _node) external view returns (bool) {
return authorizedNodes[_node];
}
/**
* @notice Sets the fulfillment permission for a given node. Use `true` to allow, `false` to disallow.
* @param _node The address of the Chainlink node
* @param _allowed Bool value to determine if the node can fulfill requests
*/
function setFulfillmentPermission(address _node, bool _allowed) external onlyOwner {
authorizedNodes[_node] = _allowed;
}
/**
* @notice Allows the node operator to withdraw earned LINK to a given address
* @dev The owner of the contract can be another wallet and does not have to be a Chainlink node
* @param _recipient The address to send the LINK token to
* @param _amount The amount to send (specified in wei)
*/
function withdraw(address _recipient, uint256 _amount)
external
onlyOwner
hasAvailableFunds(_amount)
{
withdrawableTokens = withdrawableTokens.sub(_amount);
assert(LinkToken.transfer(_recipient, _amount));
}
/**
* @notice Displays the amount of LINK that is available for the node operator to withdraw
* @dev We use `ONE_FOR_CONSISTENT_GAS_COST` in place of 0 in storage
* @return The amount of withdrawable LINK on the contract
*/
function withdrawable() external view onlyOwner returns (uint256) {
return withdrawableTokens.sub(ONE_FOR_CONSISTENT_GAS_COST);
}
/**
* @notice Allows requesters to cancel requests sent to this oracle contract. Will transfer the LINK
* sent for the request back to the requester's address.
* @dev Given params must hash to a commitment stored on the contract in order for the request to be valid
* Emits CancelOracleRequest event.
* @param _requestId The request ID
* @param _payment The amount of payment given (specified in wei)
* @param _callbackFunc The requester's specified callback address
* @param _expiration The time of the expiration for the request
*/
function cancelOracleRequest(
bytes32 _requestId,
uint256 _payment,
bytes4 _callbackFunc,
uint256 _expiration
) external {
bytes32 paramsHash = keccak256(
abi.encodePacked(
_payment,
msg.sender,
_callbackFunc,
_expiration)
);
require(paramsHash == commitments[_requestId], "Params do not match request ID");
// solhint-disable-next-line not-rely-on-time
require(_expiration <= now, "Request is not expired");
delete commitments[_requestId];
emit CancelOracleRequest(_requestId);
assert(LinkToken.transfer(msg.sender, _payment));
}
// MODIFIERS
/**
* @dev Reverts if amount requested is greater than withdrawable balance
* @param _amount The given amount to compare to `withdrawableTokens`
*/
modifier hasAvailableFunds(uint256 _amount) {
require(withdrawableTokens >= _amount.add(ONE_FOR_CONSISTENT_GAS_COST), "Amount requested is greater than withdrawable balance");
_;
}
/**
* @dev Reverts if request ID does not exist
* @param _requestId The given request ID to check in stored `commitments`
*/
modifier isValidRequest(bytes32 _requestId) {
require(commitments[_requestId] != 0, "Must have a valid requestId");
_;
}
/**
* @dev Reverts if `msg.sender` is not authorized to fulfill requests
*/
modifier onlyAuthorizedNode() {
require(authorizedNodes[msg.sender] || msg.sender == owner, "Not an authorized node to fulfill requests");
_;
}
/**
* @dev Reverts if not sent from the LINK token
*/
modifier onlyLINK() {
require(msg.sender == address(LinkToken), "Must use LINK token");
_;
}
/**
* @dev Reverts if the given data does not begin with the `oracleRequest` function selector
* @param _data The data payload of the request
*/
modifier permittedFunctionsForLINK(bytes _data) {
bytes4 funcSelector;
assembly { // solhint-disable-line no-inline-assembly
funcSelector := mload(add(_data, 32))
}
require(funcSelector == this.oracleRequest.selector, "Must use whitelisted functions");
_;
}
/**
* @dev Reverts if the callback address is the LINK token
* @param _to The callback address
*/
modifier checkCallbackAddress(address _to) {
require(_to != address(LinkToken), "Cannot callback to LINK");
_;
}
/**
* @dev Reverts if the given payload is less than needed to create a request
* @param _data The request payload
*/
modifier validRequestLength(bytes _data) {
require(_data.length >= MINIMUM_REQUEST_LENGTH, "Invalid request length");
_;
}
}
// File: browser/gists/03a079b9055f42d993d0066d6f454c6f/Oracle.sol
pragma solidity 0.4.24;